2.0 Analysis 2.1 Introduction Based on factual information gathered during the course of the investigation, certain aspects of the occurrence flight are reliably known. The helicopter commenced its flight in marginal visual meteorological conditions. The pilot intended to climb through a fog layer using rising terrain as visual reference during the climb. As the helicopter climbed the rising terrain northeast of its departure point, it was flying in an area of visibilities reduced to a few hundred feet in dense fog. Based on the ear witness observations, the helicopter did not climb above the fog layer. The helicopter was manoeuvring in the Mount Harry Davis area when the noise of the helicopter colliding with the terrain was heard. At some point prior to the accident, the helicopter entered a descent. The initiation of the descent, particularly if accompanied by a decrease in collective pitch, would have altered the sound pattern produced by the helicopter while in forward flight. This is consistent with the description by some ear witnesses of an absence of helicopter sounds prior to the sound of impact. At impact, the helicopter was heading in a southerly direction, essentially away from Mount Harry Davis and back towards its base in Houston. There are two conditions which could account for the accident: a helicopter technical malfunction or the pilot inadvertently losing his visual references with the ground. The analysis will examine these two possibilities and will review specific risk management circumstances surrounding the occurrence. 2.2 Technical Malfunction The examination of the wreckage did not reveal any evidence of a pre-impact failure of the helicopter's engine, controls, or instrumentation systems. According to the technical logs, the helicopter had been properly maintained in accordance with existing regulations and there was no record of flight control difficulties. The possibility that the particles discovered in the collective servo actuator had interfered with the spool valve during the accident flight and that such interference was causal to the accident was considered. Although three of the particles had clearly interfered with the spool valve at some point, it was impossible to determine specifically when during the 6000-hour life of the component the interference event had occurred. Nevertheless, as a result of the tests and analysis conducted, it was concluded that, if the interference had occurred during the accident flight, the force required to overcome the interference of the spool valve by shearing the particle was well within the pilot's capability. Although an aircraft malfunction, particularly a jamming of the servo actuator's spool valve, could not be conclusively ruled out as the direct cause of the accident, such an event is regarded as improbable. It was considered more likely that the pilot lost visual reference with the ground at some time while manoeuvring in the vicinity of Mount Harry Davis. 2.3 Loss of Visual Cues While flying in the operational and environmental conditions known to exist at the time, the helicopter pilot was at considerable risk of losing his external visual cues with the ground. Given the high velocity and the flight profile at impact, it is reasonable to conclude that the pilot probably did not see the ground prior to the collision. There are several elements present in this occurrence which could be considered as contributing to the loss of the pilot's outside references. For example, the pilot intended to fly the helicopter in a climb up the side of Mount Harry Davis while the helicopter was at or near its maximum all-up weight. Although the helicopter was capable of hovering flight, the additional power margin required to continue the climb over the rising terrain was limited. The pilot could, therefore, have been intent on maintaining an airspeed at least above translational speed, which may have been too fast for the visibility conditions. The flight could also have encountered an area where the ground features were uniformly covered with snow and frost. When combined with the poor visibility conditions, these circumstances could have resulted in a whiteout situation. The conditions inside the helicopter may also have combined to further restrict the flight visibility. Given the existing temperature and dew point, and given that the warmly clad occupants were likely increasing the cabin's relative humidity level, it is possible that moisture condensed on the interior of the helicopter's windscreen. This would have impaired the pilot's vision to external references. As previously discussed, given the discovery of the metallic fragments in the collective servo actuator, a control difficulty was a remote possibility which could not be conclusively ruled out. Such a technical problem could have caused the pilot to focus his attention inside the cockpit at a critical moment during the flight and resulted in his loss of visual reference with the ground. All of the above could have resulted in or contributed to the loss of external visual references. The reason for the pilot's probable loss of visual cues could not be determined. Whatever the reason, however, the pilot would have been faced with one of the most hazardous situations to be encountered in helicopter flying: that is, immediate transition from flight with visual reference to flight with reference to instruments. This would have occurred while in a critical phase of flight--close to the ground while in a high performance regime and in mountainous terrain. 2.4 Spatial Disorientation The pilot in this occurrence had the added disadvantages of not being experienced or current in instrument flying, and flying an aircraft which was only marginally equipped for instrument flight. A pilot suddenly exposed to IMC flight under these conditions is known to be susceptible to spatial disorientation. The high velocity and unusual yaw attitude at impact are indications of flight consistent with spatial disorientation. 2.5 Risk Management It could not be determined why the pilot departed in marginal weather conditions and into flight visibilities he had earlier described as four or five tree-top lengths. There was no evidence that the pilot was under pressure from the customers to complete the revenue flight. He intended to repeat the cloud-breaking procedure immediately after the accident flight for the purpose of a pleasure trip to go fishing with his friends. The pilot had successfully flown a trip earlier that day in marginal weather. He had flown a similar flight the day before and, according to his entries in his log-book, he had flown in marginal weather conditions on a number of occasions. In addition, during his career flying in the mountains of British Columbia, he had undoubtedly observed other pilots doing the same. It is possible, given his previous success in completing the cloud-breaking procedure and given his awareness of other pilots using the same technique, that his sense of the dangers inherent in the procedure had been diminished. His comment earlier that day to the FSS specialist that the weather was helicopter VFR may have been a reflection of this perception. 3.0 Conclusions 3.1 Findings The pilot was certified, trained, and qualified for VFR flight in accordance with existing regulations. The pilot had extensive experience in mountain and marginal weather operations. The pilot was not trained, experienced, or qualified for flight in instrument meteorological conditions. The aircraft was certified, equipped, and maintained in accordance with existing regulations and approved procedures. The helicopter was not certified or equipped for flight in instrument meteorological conditions. Some metallic particles, originating from the component's manufacturing process, were found in the collective servo actuator. Three of these particles bore evidence of having interfered with the movement of the spool valve at some time during the life of the component. There was no evidence found of any airframe failure prior to or during the flight. The pilot's intent was to climb above a layer of fog by using the rising terrain as a visual reference. The visibility along the helicopter's flight path was reduced to 1/4 mile or less in fog. While in the Mount Harry Davis area, the pilot was operating in flight visibilities which were below existing VFR criteria. Prior to impact, the pilot had probably lost his external visual cues and the helicopter was likely in instrument meteorological conditions. The pilot had successfully employed the technique of using rising terrain as a visual reference to climb above a fog layer on two other known occasions. This technique is widely known in the helicopter pilot community; however, the frequency of its use could not be determined. 3.2 Causes The pilot, while attempting to climb through a fog layer by using rising terrain as a visual reference, most likely lost the visual cues required for flight in visual meteorological conditions (VMC). The helicopter struck a ridge, probably while the pilot attempted to regain his visual reference with the ground. The pilot's decision to use the rising terrain as a visual reference under the existing visibility conditions was a contributing factor to this accident. 4.0 Safety Action 4.1 Action Taken 4.1.1 Hydraulic Servo Contamination On 15 December 1994, Transport Canada (TC) advised the Federal Aviation Administration (FAA) of the metallic contamination found in the helicopter's collective servo actuator. In their correspondence, TC suggested that the FAA ensure that the servo manufacturer takes appropriate quality control/assurance actions. 4.1.2 Interim TSB Aviation Safety Recommendations Based on information compiled during this investigation, and frequent evidence of a lack of appreciation on the part of helicopter operators/pilots of the risks involved in conducting VFR flights into adverse weather, especially in mountainous terrain, the Board notified the Minister of Transport in August 1994 of three interim Safety Recommendations. 4.1.2.1 Flight Into Adverse Weather - Risk Awareness A TSB safety study on VFR into adverse weather found that VFR-into-instrument- meteorological-conditions (IMC) accidents accounted for only 6% of the total number of aircraft accidents in Canada; yet, they involved 23% of all fatal accidents and took the lives of 418 persons between 1976 and 1985. Half of the VFR-into-IMC accidents had occurred in mountainous or hilly terrain; approximately 10% of VFR-into-IMC accidents involved helicopters, and one third of these were fatal. Since the release of the safety study and its associated recommendations in December 1990, there have been 10 commercial helicopter accidents in Canada involving VFR flight in adverse weather, resulting in six fatalities. The Board believes that some VFR-rated helicopter pilots, especially those operating in mountainous areas, have adopted the practice of intentionally penetrating localized areas of extremely reduced visibility in order to reach areas of better weather. Commercial helicopter accidents in adverse weather continue, despite frequent emphasis in TC safety newsletters and presentations on the importance of adhering to established VFR limits. The Board believes that proper training and education are important in the prevention of adverse weather accidents; however, the Board was not aware of any substantial measures in this vein being taken by TC or the helicopter industry following the recommendations of its 1990 study. Therefore, the Board recommended that: The Department of Transport, in consultation with the aviation industry, implement a special safety campaign to inform the helicopter community of the inherent risks involved in the ad hoc practice of penetrating cloud/fog in VFR operations, particularly in mountainous regions. In its response to recommendation A94-18, TC has indicated that it will make extra efforts in this regard by publishing a feature article in the helicopter safety newsletter, Vortex; this newsletter is distributed to every licensed helicopter pilot in Canada. Also, Regional Aviation Safety Officers (RASOs) across the country will be provided with a special promotional package, so that they may distribute it to the helicopter industry during their regional visits. 4.1.2.2 Regulatory Compliance Industry Self-Regulation ANO V, No. 3, Para 6 does not permit VFR flight in cloud. The Board believes that the extent to which the unsafe practice of cloud penetration is prevalent might suggest a lack of respect for the need for regulatory compliance; operators/pilots may feel that there is only a remote possibility of being found in violation of the ANO. In a 1991 TSB survey of commercial pilots, 38% of respondents stated that TC's inspections of company facilities are not sufficiently frequent to ensure that regulations are respected. It is understood that Transport Canada has not recorded any violations under ANO V, No. 3, Para 6 in the mountainous regions of western Canada in the last ten years. The Board is well aware that climatic conditions in many locations prevent some VFR- only operators from conducting their business at certain times of the year. However, if these operators ignore the weather limits in the ANO, they negate the safety buffer provided by the regulation, and put themselves and their passengers at risk. Furthermore, the Board believes that within the helicopter industry in general, the practice of pressing-the-weather is tacitly accepted and is viewed as a part of doing business. There does not appear to be self-regulation through condemnation by peers in this regard within the industry. The Board believes that neither the regulator nor the commercial helicopter industry are effectively ensuring compliance with established weather limits. Therefore, the Board recommended that: The Department of Transport place increased emphasis on achieving compliance with respect to VFR weather limits for commercial helicopter operations; and The Department of Transport, in conjunction with industry, explore measures to counter attitudes that pressing-the-weather is an acceptable practice in commercial VFR helicopter operations. In its response to recommendation A94-19, TC indicated that regional air carrier branches will be tasked to place increased emphasis on commercial helicopter operations in adverse weather conditions and that an Air Carrier Advisory Circular (ACAC) will be issued emphasizing the hazards of intentionally penetrating localized areas of reduced visibility. With respect to recommendation A94-20, TC indicated that a letter will be sent to the major helicopter associations to impress upon their members that pressing-the-weather is not an acceptable practice.